1. Field of the Invention
The present invention relates generally to a backlight module of the liquid crystal display, and more particularly, relates a backlight module with the electromagnetic-induction system.
2. Description of the Prior Art
Development of computer is early spring up from the mainframe, its evolutional period goes through personal computer (PC), notebook, personal digital assistant (PDA) and desknote. Recently, the computer industry has developed the era of Tablet PC is defined a PC between PDA and notebook. Tablet PC is presented to the public that means Tablet PC is the evolution of the laptop, that is, Tablet PC is similar to a portable PC with a handwriting recognition system. Tablet PC has various especially functions, such as (digital touch panel and digital pen) (saving files in time), that is different with operation function of past PC. Touch screen of a general Table PC can be turned up or down with 180 degree such that the original shape of the notebook product becomes to a portable handwriting liquid crystal panel for user required. Furthermore, in addition to Tablet PC with all of functions of PC, the best feature in Tablet PC is an electromagnetic-induction module thereof. User can perform the handwriting model with touch pen to input data. This operation will be more close to general function of writing and reading for human. User can input and operate on touch screen by only using touch pen. Accordingly, we can offer the best input model in different environments for user. Moreover, Table PC can offer more natural input method to the user that is not familiar with operation of PC by an interface of handwriting, so as to substitute for traditional input method used keyboard, and to reduce barrier of learning PC.
Because a handwriting recognition system could replace the mouse, and is more suitable than the mouse to let the user input words and patterns by user's hands, improvement of the handwriting recognition system is a hot and important field of current computer technology. The original intention of the handwriting recognition system, there are a electromagnetic-induction system, and the conventional electromagnetic-induction systems with a electromagnetic pen and a digital tablet. There is an oscillating circuit that consists of LC in the electromagnetic pen. If the pen point is touched, the amount of inductance will be changed that results in the variation of oscillating frequency. The amount of inductance is increased when touching the pen point and increasing pressure so the variation of oscillating frequency is also increased. Therefore, the variation of the pressure on the pen point can be detected by way of the variation of oscillating frequency. There are two switches on the sidewall of the electromagnetic pen, the emitted frequency of the electromagnetic pen can be changed with the capacitance variation of the LC device that is produced by pushing down or setting free the switches. Furthermore, the tablet comprises a detector, an amplifier and an analog-digital converter. In the conventional tablet, there is a detected loop in the center region of the tablet, with one-way antennas located on the double faces of the detected loop, wherein the one-way antennas are equidistantly arranged in order by way of using array. The main purpose of the one-way detected loop is only applied to receive the electromagnetic wave that is emitted by the electromagnetic pen. When the electromagnetic pen emits the electromagnetic wave, the one-way antennas receive the electromagnetic wave, and then the tablet can obtain correlative information by the electromagnetic induction.
Nowadays Table PC just utilizes foregoing electromagnetic-induction system so as to enable to handwriting input. Usually there are two organized structures in general Table PC, one is a liquid crystal display with a backlight module, and the other is the electromagnetic-induction system with antenna circuit. However, regarding advanced technology industry, product shrink is one of important milestone of development.
In view of foregoing, how to harmonize about a liquid crystal display with a backlight module and the electromagnetic-induction system with antenna circuit so as to shrink the size and thickness of product, reduce process cost, and enhance penetration efficiency of electromagnetic-induction, those are important subjects.